Device for tensioning tubular fabric whilst it is being knitted in a circular knitting machine for manufacture of socks and the like



Dec. 20, 1966 v. LUcHl 3,292,394

v `DEVICE FOR TENSIONING TUBULAR FABRIC WHILST IT IS BEING' KNITTED IN A CIRCULAR KNITTINC' MACHINE FOR MANUFACTURE OF SOCKS AND THE LIKE Filed Deo. 14, 1964 2 sheets-sheet 1 Dec. 20, 1966 v. LUCI-u DEVICE FOR TENSIONING TUBULAR FABRIC WHILST IT IS BEING KNITTED IN A CIRCULAR KNITTING MACHNE FOR MANUFACTURE OF SOCKS AND THE LIKE 2 Sheets-Sheet 2 Filed Dec. 14, 1964 United States Patent Oice 3,292,394 Patented Dec. 20,- 1966 3,292,394 DEVICE FOR TENSIONING TUBULAR FABRIC WHILST IT IS BEING KNITTED IN A CIRCU- LAR KNI'ITING MACHINE FOR MANUFAC- TU'RE OF SOCKS AND THE LIKE Vinicio Luchi, Firenze, Italy, -assignor to Solis Societ a Responsabilit Limitata, Firenze,l Italy, a corporation of Italy Filed Dec. 14, 1964, Ser. No. 418,180 Claims priority, application Italy, Dec. 16, 1963, 26,450/63 Claims. (Cl. S6- 149) The invention relates to a device for tensioning tubular lfabric Whilst i-t is being Iknitted yin a circular knitting machine for manufacture of socks and the like, the machine having a rotary needle cylinder and control means for said needles which are contained Iin tricks .formed in the needle cylinder. The invention lis particularly applicable to a knitting machine in which the needle cylinder extends axially in both directions from the knitting zone.

According to the invention, there is provided in a circular knitting machine having a needle cylinder for the production of socks and like fabrics, a fabric tensioning device comprising a member mounted within the needle cylinder for reciprocating movement along the axis of said cylinder, a plurality of elements supported on said member for axial movement therewith, and for rad-ial movement, into engagement with the fabric, said elements having teeth inclined to grip the fabric during movement of said member in one direction only, and means for maintaining rtension on the fabric during axial movement of said member and said elements in the opposite direction.

In .one embodiment, the said members are small cylin` ders which are axially movable out of phase with each other, and each supporting toothed elements so that the toothed elements on at least one of .the members are always in gripping engagement -with the fabric |being formed to assure the tension thereof.

The invention will be better understood from the following dscription of one embodiment of the invention which is given by way of example with reference to the accompanying drawings, in which:

FIG. l is an axial section of a portion of the needle cylinder (shown diagrammatically) containing two small coaxial and reciprocally movable cylinders having toothed elements for tensioning a sock;

FIG. 2 is a section, to a different scale, through the control means for moving the cylinders of the tensioning device;

FIG. 3 is an enlarged detail of FIG. 1 showing a sock being engaged 4between the toothed elements on one of the tensioning cylinders `and the inner surface of the needle cylinder to tension the sock fabric;

FIGS. 4 and 5 show one of the axially movable cylinders, F-IG. 4 being a side elevation part sectioned and FIG. 5 being a view on Ithe broken line V-V of FIG. 4;

FIGS. y6 and 7 are views similar to FIGS. 4 and 5 of the other axially movable cylinder;

FIG. 8 is an axial section of the tensioning device shown iitted to a rotary cylinder circular knitting machine.

As is shown in the accompanying drawing, the circular knitting machine comprises a needle cylinder having a main part, which co-operates with an extension in the form of a second cylinder "1a, coaxially thereabove, to form the tubular fabric M in the working zone A. lFor the sake of clarity, the needles are not shown in FIG. 1. A ta'ble 3 shown diagrammatically in FIG. `8 is designed to centre and support the needle cylinder 1, and a bevel gear 5 is seen to mesh with a bevel rim of the cylinder to eifect rotation of the cylinder. A geared rim 7 on the needle cylinder 1 drives a shaft 10 through a pinion 9 on the shaft. The shaft, which is parallel to the axis of the needle cylinder 1, has a pinion f1.1. a-t its opposite end meshing with a geared rim 1-3 on a plate 15 which is coaxial wit-h, and spaced from, the needle cylinder 1 and is also designed to support the means for driving the socktensioning device. 'Ihe plate 15 is mounted on supporting and centering members 17 carried by a structure 19 integral with the stationary frame of the machine. The plate 15 rotates at the sarne vrotational speed as the needle cylinder.

In addition, the machine has an annular lipaforming member 21, mounted by means of an intermediate annular support 2'3 on the lower end of the cylinder 1a, which member is shaped aro-und its inner periphery to provide a smooth dcwnwardlyprojecting lip over which the tubular fabric being formed is passed, leaving the lip in an upward direction (as seen in FIG. 1) instead of the conventional downward direction. As a result, the fabric leaves the machine reversed with respect to -the fabric which leaves the machine in the conventional downward direction.

To facilitate the mechanical tensioning of the fabric, the internal mnular surface 21a (see F-IG. 3) of the meniber 2.1 projects slightly beyond the periphery of the support 23 and has a profile which is slightly convex towards the interior of the passage for the fabric M being formed, the outer wall of `this passage being defined by .the supporting member 23 and thereabove by a tubular element 27, which rotates with the cylinder 1a and thus with the cylinder 1. The cylinders 1-1a are made in the conventional manner with the longitudinal tricks for receiving the needles and with arcuate tricks for the welt hooks 1x (see FIG. 8) which slide over an arcuate path in the uppenpor-tion of the cylinder 1. 'Iihese hooks are operated by an annular cam carried by a tubular member 2,9 co axial with the cylinder 1 and supported rigidly by the table 3. In FIG. 1 the conventional members of the needle cylinder are indicated by dotted lines.

As shown .in FIG. 2, .the plate 15 carries a central movable member 31 which is held in position by retaining members 33 which are readily releasable to permit removal of the member I31. A sleeve 35 passes axially through the member 31 in screw-threaded engagement therewith for adjustment of its position, and is secured by means of a lock nut 37. The sleeve 35 has an axial bore with two different diameters, the larger lbeing arranged to slidably accommodate a tubular rod 39 which is coaxial with the needle cylinder and is upwardly extended; the tubular rod in its turn slidably `accommodating a stem 41 which also extends beyond the lower end of the rod into -the smaller diameter bore in said sleeve 35.

The tubular rod 39 and stem 41 are provided with longitudinally extended diamet-ral slots 43 and 45, respectively, through which passes a pin 47 securedto the sleeve 35. Thus through the drive 7, 9, 11, i13 (FIG. S) and the plate 15, to which the movable element 31 and the sleeve 35 are rigidly secured, the rotational motion of the cylinder 1 is transmitted to the tubular -rod 39 and to the internal stem 41, the latter being capable of sliding axially. An axial cam 49 is rigidly secured to the ste-m 39 and is engaged with the stem through pins 51, which extend in longitudinal slots 53 formed in the tubular rod 3:9. A second cam 55, similar to the cam 49, is rigidly secured to the Itubular rod 39 by means of a pin 57. The two cams 49 Aand 55 have a similar profile but they are mounted in such a manner that the two proles are offset with respect to each other. The two cams 49, 55 co-operate with tappet rollers 59, 61 which are borne by arms 59a, 61a -rigid with a column or post 63 extending upwardly from the stationary frame 19 which also supports the guide means for the rotary plate 15. A spring 65 urges the stem 41 upwardly to press the cam 49 against the tappet roller 59, and a spring 67 likewise urges the tubular rod 39 upwardly. The two springs 65, 67 are adjustable so that their thrust can be adjusted to suit the Atype of fabric being knitted. For this purpose, a set screw 65a is fitted axially in the lower end of the sleeve 35 to provide an abutment for the spring 65. Axial movement of the sleeve 35 serves to vadjust the action of the spring 67.

A small cylindrical member 69 (FIG. 4) supported on the upper end of the stem 41, is provided with an annular groove 69a around its lower end portion. From the groove to the upper end, the member 69 is formed with an even number of longitudinal rgrooves 69b in radial planes, the depth of Ithe grooves increasing in the upward direction.

A second cylindrical member 73 (FIG. 6*) is secured by a screw 71 (FIG. 1) to the upper end of the tubular rod 39, the member 73 being formed with an annular groove 73a around its upper portion. From this groove to the lower end of the member 73, grooves 73b are formed therein equal in number to the grooves 69b. These grooves 7311 extend longi-tudinally in radial planes and are aligned in t-he longitudinal -direction with the grooves 69h. The stem 4'1 passes through the small cylinder 73.

Two different series of laminar elements 75, 79 are housed in the grooves 69b-73b and each element of one series is interposed between two Vof the other series. The laminar elements 75 (FIG. 1) of one series are each provided with a butt 75a, which is received in ruhe groove 73a, the laminar elements 75 thus being axially movable together with the cylinder member 7 3. An annular sprin-g 77 engages in suitable recesses in the outer edge of the elements 75, below the butts 75a, so Athat the upper portions of the elements 75 which are received in alternate grooves 69b in the member 69, are biased resiliently to project from these grooves. The l'aminar elements 79 of the second series are each provided with a butt 79a which is received in the groove 69a. An annular spring 81 engages in recesses inthe external edges of .the laminar elements 79, so that the upper portions of the laminar elements 79 which are received in the intermediate grooves 69b in the member 69, are biassed resiliently to project from t-hese grooves. are engaged by their butts 79a with the small cylinder member 69, so that they participate in the axial movements of the member 69.

The 'butts 75a and 79a thus `act as pivots about which the respective seri-es of elements 75 and 79 are expanded under the action of the springs 77 and 81.

The elements 75 and 79 are provided, along the outer edges of their upper portions, wi-th ratchet teeth 75h and 79b respectively, to co-operate with the projecting profile 21a of the annular member 21 in gripping the tubular fabric.

The fabric M being formed is inserted and is engaged between the member 21 -and the toothed portions of the laminar elements 75, 79 which are movable together with their respective small cylinder members 73 and 69. These cylinder members, being supported by the tubular rod 39 and the stem 41 respectively, are biassed resiliently upwardly by the springs 67 and 65 respectively, as a result of which the fabric is stretched in the working zone A. The cams 49 and 55 in this arrangement do not contact the fixed tappets 59, 61. Periodically, at each revolution of the needle cylinder and thus at each revolution of the cams, but out of phase with each other, these cams contact the respective tappets and effect lowering of the small cylinder members 69 and 73 against the action of the Irespective springs. Considering, for example, the action of the cylinder member 69, it will be noted that when the highest part of `the cam 49 contacts The laminar elements 79 f the stationary tappet 59, the cam forces the stem 41 downwards against the action of the spring 65, and thus the member `69 is lowered. In thisFdownward or retraction stroke of the member 69, the laminar elements 75 attached to the small cylinder member 73 are kept biassed upwardly and thus tension the fabric, whilst the laminar elements 79 attached to the member 69 are moved downwards. As soon as the raised portion of the cam 49 moves out of contact with the fixed tappet 59, the spring 65 returns the stem .41 upwardly and the teeth 79b grip and tension the fabric. 'I'.his tension is also maintained by the teeth 79b when subsequently the member `73 is lowered and with it the laminar elements 75, said elements having maintained the tension on the fabric during the lowering of the laminar elements 79. Thus Ithe continuity of the upwardly directed tensioning of the fabric M -to its completion is assured.

The attachment may be readily attached to and detached from a machine of the type described or similar types.

The tensioning device acts on the fabric without damaging it, since fabrics of the type under consideration have substantial resistance to tension such as will :be exerted by the teet-h- 75b and 79b.

The drawings illustrate only one embodiment which is given by way of example only lbut this embodiment can be modified considerably wit-hout departing from the scope of the invention. For example, tooth profiles different from the inclined teeth illustrated in the drawings may be provided to engage the fabric.

I claim:

1. In a circular knitting machine, having a needle cylinder, for the production of socks and like fabrics, a fabric tensioning device comprising a first member mounted in said cylinder for reciprocal movement along the axis of the cylinder,

a set of first elements mounted on said first member for axial movement therewith and for radial movement,

teeth on said elements for engaging said fabric and for gripping the fabric during movement of said first member in one direction only,

means biassing said elements radially outwardly into contact with the fabric,

a second member mounted in said cylinder for reciprocal movement along the axis of the cylinder,

a set of second elements mounted on said second member for axial movement therewith and for `radial movment,

teeth on said second elements for engaging said fabric and for gripping said fabric during movement of said second member in said one direction only,

means biassing said second elements radially outwardly into contact with the fabric, and i means for axially moving said sets of elements alternately thereby to retract each set of elements in turn whilst the other set of elements is maintaining tension on the fabric being generated.

2. A fabric tensioning device according to claim 1 wherein said first toothed elements are disposed between the adjacent ones of said second toothed elements.

3. A fabric tensioning device according to claim 1 wherein each said member is a cylindrical member having therein longitudinal grooves lying in radial planes, said elements being of laminar shape, pivot means being provided onsaid elements to support the elements for pivotal movement in said grooves, and wherein each said biassing means comprises an annular spring sur-rounding the respective set of elements and acting on a part of each element on the opposite side of the pivot means from its fabric-engaging teeth.

4. A fabric tensioningdevice according to claim .1 wherein said elements co-operate with a radially-inwardly projecting portion of theneedle cylinder wall to grip the 5 6 fabric therebetween, said wall portion having a surface is being tensioned thereby to effect a quick retraction which is convex in axial section. stroke of said t-oothed elements.

5. A fabric tensioning device according to claim 1 wherein said means for axially moving ,said sets of ele- References Cited by the Examiner ments comprise 5 FOREIGN PATENTS two coaxial rods each supporting one of said members, 1 159 224 2/1958 France i two axial cams, each mounted on a separate one of 955184 4/1964 Great tain said rods,

springs biassing said rods in the axial `direction in which MERVIN STEIN Primary Exam,er

the fabric is to be tensioned and l0 tappets acting on said axial cams to urge the rods 1u DONALD W' PARKER Examme" the axial direction opposite to that in which the fabric P. C. FAW, R. FELDBAUM, Assistant Examiners. 

1. IN A CIRCULAR KNITTING MACHINE, HAVING A NEEDLE CYLINER, FOR THE PRODUCTION OF SOCKS AND LIKE FABRICS, A FABRIC TENSIONING DEVICE COMPRISING A FIRST MEMBER MOUNTED IN SAID CYLINDER FOR RECIPROCAL MOVEMENT ALONG THE AXIS OF THE CYLINDER, A SET OF FIRST ELEMENTS MOUNTED ON SAID FIRST MEMBER FOR AXIAL MOVEMENT THEREWITH AND FOR RADIAL MOVEMENT, TEETH ON SAID ELEMENTS FOR ENGAGING SAID FABRIC AND FOR GRIPPING THE FABRIC DURING MOVEMENT OF SAID FIRST MEMBER IN ONE DIRECTION ONLY, MEANS BIASSING SAID ELEMENTS RADIALLY OUTWARDLY INTO CONTACT WITH THE FABRIC, A SECOND MEMBER MOUNTED IN SAID CYLINDER FOR RECIPROCAL MOVEMENT ALONG THE AXIS OF THE CYLINDER, 